The present invention relates to an apparatus for changing the position of flexible, flat objects, in particular printed products, arriving on a first conveyor in an overlapping stream.
An apparatus of this type is disclosed by CH Patent Number 677 778. Arranged in the downstream end region of a first conveyor, between the conveyor tapes forming a conveying plane, is a position-changing device. It has two disks which are arranged beside each other in the conveying plane and driven in opposite directions, on each of which a displacement cam is situated eccentrically. These displacement cams are intended in each case to come into contact with the rear edge of each object arriving on the first conveyor in an overlapping stream, to accelerate said object in the conveying direction and to feed it to the second conveyor. The latter is assigned a braking device, which is intended to brake the objects accelerated by the rotation of the disks to the conveying speed of the second conveyor. The high speeds and retardations associated with this apparatus, in particular in the case of a high processing capacity, constitute a considerable stress on the objects, and can lead to damage. Furthermore, in order to achieve a specific desired spacing between the objects on the second conveyor, the distance of the displacement cams from the axes of rotation of the disks, and the rotational speed of the disks, depend on one another and also on the conveying speeds of the first and second conveyors, the desired spacing and the spacing of the objects in the arriving overlapping formation, for which reason rather closer limits are placed on the ability of the apparatus to be used.
In a further apparatus, which is disclosed in CH 631 410 and is connected between a first and a second conveyor, printed products are conveyed using displacement means which are fixed to a toothed chain and are provided with contact rollers, which are driven in the opposite direction to the direction of motion of the displacement means. The printed products are therefore not gripped immediately by the displacement means but only during the transfer between the first and the second conveyor. The duration of the synchronization procedure depends on the printed products, so that universal use of the apparatus is called into question.
The published specification WO 95/03989 discloses a further apparatus in which printed products are transferred from a first to a second conveyor. The second conveyor has a chain, on which transport clamps are firmly mounted at equal intervals from one another. The transport clamps are therefore filled periodically with a printed product at a transfer point. A position-changing device is provided to ensure that the printed products in each case arrive at the second conveyor at the correct time. The requirements on the first conveyor and the preceding conveying systems are therefore very high, so that if there are irregularities in the feed, disruptions can easily occur.
It is therefore an object of the present invention to develop the apparatus of known type in such a way that it can be used more universally, with more careful handling of the objects.
The above and other objects and advantages of the present invention are achieved by the provision of an apparatus for changing the position of the objects arriving on a first conveyor, for example, in an overlapping stream, and which comprises a position changing device arranged in the region of the first conveyor and which has a displacement means which is moved along a movement path. During at least one section of the movement path, the displacement means is driven by means of a drive at a higher speed than the conveying speed of the first conveyor and so as to feed each object delivered to the position changing device to a second conveyor, which is driven at a conveying speed that is higher than that of the first conveyor. The one section of the movement path extends at least approximately rectilinearly and in the conveying direction, and the drive drives the displacement means in the one section at a speed which is at least approximately equal to the conveying speed of the second conveyor.
The at least approximately rectilinear movement path of the displacement means permits the speed of the objects to be kept low; it never needs to be higher than the conveying speed of the second conveyor, which permits high processing capacities with careful handling of the object.